In recent years, progress has been made in the treatment of cancer, particularly with the development of targeted therapeutics. However, there is very little advancement in the treatment of tumor metastasis, which remains the major cause of mortality of cancer patients. Tumor metastasis being responsible for ˜90% of all cancer deaths (1, 2). Metastasis is a multi-step process wherein a primary tumor spreads from its initial site to secondary tissues and organs (3-5). This metastatic process is selective for cells that succeed in cell migration, invasion, embolization, survival in the circulation, arrest in a distant capillary bed, and extravasation into and multiplication within the organ parenchyma. Failure at any of these steps could block the entire metastatic process. Since tumor spreading is responsible for the majority of deaths of cancer patients, there is a demand for the development of therapeutic agents that inhibit tumor metastasis.
Most current treatments for metastatic cancers are aimed to kill or stop the growth of primary cancer cells (6-8). Although tumor cell migration and invasion are critical steps in the process of tumor metastasis (9-12), inhibitors of tumor cell migration are not presently available to treat metastatic cancer. Therefore, it is desirable to develop small molecule inhibitors targeting tumor cell migration.